Refactor sidebar assignee&milestone&project selectors (#32465)

Follow #32460

Now the code could be much clearer than before and easier to maintain. A
lot of legacy code is removed.

Manually tested.

This PR is large enough, that fine tunes could be deferred to the future if
there is no bug found or design problem.

Screenshots:

<details>

![image](https://github.com/user-attachments/assets/35f4ab7b-1bc0-4bad-a73c-a4569328303c)

</details>

modules/base/tool.go

@@ -147,6 +147,9 @@ func StringsToInt64s(strs []string) ([]int64, error) {
 	}
 	ints := make([]int64, 0, len(strs))
 	for _, s := range strs {
+		if s == "" {
+			continue
+		}
 		n, err := strconv.ParseInt(s, 10, 64)
 		if err != nil {
 			return nil, err

modules/base/tool_test.go

@@ -152,6 +152,7 @@ func TestStringsToInt64s(t *testing.T) {
 	}
 	testSuccess(nil, nil)
 	testSuccess([]string{}, []int64{})
+	testSuccess([]string{""}, []int64{})
 	testSuccess([]string{"-1234"}, []int64{-1234})
 	testSuccess([]string{"1", "4", "16", "64", "256"}, []int64{1, 4, 16, 64, 256})
 

modules/container/set.go

@@ -31,8 +31,8 @@ func (s Set[T]) AddMultiple(values ...T) {
 	}
 }
 
-// Contains determines whether a set contains the specified elements.
-// Returns true if the set contains the specified element; otherwise, false.
+// Contains determines whether a set contains all these elements.
+// Returns true if the set contains all these elements; otherwise, false.
 func (s Set[T]) Contains(values ...T) bool {
 	ret := true
 	for _, value := range values {

modules/container/set_test.go

@@ -18,7 +18,9 @@ func TestSet(t *testing.T) {
 
 	assert.True(t, s.Contains("key1"))
 	assert.True(t, s.Contains("key2"))
+	assert.True(t, s.Contains("key1", "key2"))
 	assert.False(t, s.Contains("key3"))
+	assert.False(t, s.Contains("key1", "key3"))
 
 	assert.True(t, s.Remove("key2"))
 	assert.False(t, s.Contains("key2"))

modules/templates/helper.go

@@ -31,6 +31,7 @@ func NewFuncMap() template.FuncMap {
 		"ctx": func() any { return nil }, // template context function
 
 		"DumpVar": dumpVar,
+		"NIL":     func() any { return nil },
 
 		// -----------------------------------------------------------------
 		// html/template related functions

routers/web/repo/compare.go

@@ -788,19 +788,11 @@ func CompareDiff(ctx *context.Context) {
 
 		if !nothingToCompare {
 			// Setup information for new form.
-			retrieveRepoMetasForIssueWriter(ctx, ctx.Repo.Repository, true)
+			pageMetaData := retrieveRepoIssueMetaData(ctx, ctx.Repo.Repository, nil, true)
 			if ctx.Written() {
 				return
 			}
-			labelsData := retrieveRepoLabels(ctx, ctx.Repo.Repository, 0, true)
-			if ctx.Written() {
-				return
-			}
-			RetrieveRepoReviewers(ctx, ctx.Repo.Repository, nil, true)
-			if ctx.Written() {
-				return
-			}
-			_, templateErrs := setTemplateIfExists(ctx, pullRequestTemplateKey, pullRequestTemplateCandidates, labelsData)
+			_, templateErrs := setTemplateIfExists(ctx, pullRequestTemplateKey, pullRequestTemplateCandidates, pageMetaData)
 			if len(templateErrs) > 0 {
 				ctx.Flash.Warning(renderErrorOfTemplates(ctx, templateErrs), true)
 			}

routers/web/repo/issue.go

@@ -431,7 +431,7 @@ func issues(ctx *context.Context, milestoneID, projectID int64, isPullOption opt
 		return 0
 	}
 
-	retrieveProjects(ctx, repo)
+	retrieveProjectsForIssueList(ctx, repo)
 	if ctx.Written() {
 		return
 	}
@@ -556,37 +556,147 @@ func renderMilestones(ctx *context.Context) {
 	ctx.Data["ClosedMilestones"] = closedMilestones
 }
 
-// RetrieveRepoMilestonesAndAssignees find all the milestones and assignees of a repository
-func RetrieveRepoMilestonesAndAssignees(ctx *context.Context, repo *repo_model.Repository) {
+type issueSidebarMilestoneData struct {
+	SelectedMilestoneID int64
+	OpenMilestones      []*issues_model.Milestone
+	ClosedMilestones    []*issues_model.Milestone
+}
+
+type issueSidebarAssigneesData struct {
+	SelectedAssigneeIDs string
+	CandidateAssignees  []*user_model.User
+}
+
+type IssuePageMetaData struct {
+	RepoLink             string
+	Repository           *repo_model.Repository
+	Issue                *issues_model.Issue
+	IsPullRequest        bool
+	CanModifyIssueOrPull bool
+
+	ReviewersData  *issueSidebarReviewersData
+	LabelsData     *issueSidebarLabelsData
+	MilestonesData *issueSidebarMilestoneData
+	ProjectsData   *issueSidebarProjectsData
+	AssigneesData  *issueSidebarAssigneesData
+}
+
+func retrieveRepoIssueMetaData(ctx *context.Context, repo *repo_model.Repository, issue *issues_model.Issue, isPull bool) *IssuePageMetaData {
+	data := &IssuePageMetaData{
+		RepoLink:      ctx.Repo.RepoLink,
+		Repository:    repo,
+		Issue:         issue,
+		IsPullRequest: isPull,
+
+		ReviewersData:  &issueSidebarReviewersData{},
+		LabelsData:     &issueSidebarLabelsData{},
+		MilestonesData: &issueSidebarMilestoneData{},
+		ProjectsData:   &issueSidebarProjectsData{},
+		AssigneesData:  &issueSidebarAssigneesData{},
+	}
+	ctx.Data["IssuePageMetaData"] = data
+
+	if isPull {
+		data.retrieveReviewersData(ctx)
+		if ctx.Written() {
+			return data
+		}
+	}
+	data.retrieveLabelsData(ctx)
+	if ctx.Written() {
+		return data
+	}
+
+	data.CanModifyIssueOrPull = ctx.Repo.CanWriteIssuesOrPulls(isPull) && !ctx.Repo.Repository.IsArchived
+	if !data.CanModifyIssueOrPull {
+		return data
+	}
+
+	data.retrieveAssigneesDataForIssueWriter(ctx)
+	if ctx.Written() {
+		return data
+	}
+
+	data.retrieveMilestonesDataForIssueWriter(ctx)
+	if ctx.Written() {
+		return data
+	}
+
+	data.retrieveProjectsDataForIssueWriter(ctx)
+	if ctx.Written() {
+		return data
+	}
+
+	PrepareBranchList(ctx)
+	if ctx.Written() {
+		return data
+	}
+
+	ctx.Data["CanCreateIssueDependencies"] = ctx.Repo.CanCreateIssueDependencies(ctx, ctx.Doer, isPull)
+	return data
+}
+
+func (d *IssuePageMetaData) retrieveMilestonesDataForIssueWriter(ctx *context.Context) {
 	var err error
-	ctx.Data["OpenMilestones"], err = db.Find[issues_model.Milestone](ctx, issues_model.FindMilestoneOptions{
-		RepoID:   repo.ID,
+	if d.Issue != nil {
+		d.MilestonesData.SelectedMilestoneID = d.Issue.MilestoneID
+	}
+	d.MilestonesData.OpenMilestones, err = db.Find[issues_model.Milestone](ctx, issues_model.FindMilestoneOptions{
+		RepoID:   d.Repository.ID,
 		IsClosed: optional.Some(false),
 	})
 	if err != nil {
 		ctx.ServerError("GetMilestones", err)
 		return
 	}
-	ctx.Data["ClosedMilestones"], err = db.Find[issues_model.Milestone](ctx, issues_model.FindMilestoneOptions{
-		RepoID:   repo.ID,
+	d.MilestonesData.ClosedMilestones, err = db.Find[issues_model.Milestone](ctx, issues_model.FindMilestoneOptions{
+		RepoID:   d.Repository.ID,
 		IsClosed: optional.Some(true),
 	})
 	if err != nil {
 		ctx.ServerError("GetMilestones", err)
 		return
 	}
+}
 
-	assigneeUsers, err := repo_model.GetRepoAssignees(ctx, repo)
+func (d *IssuePageMetaData) retrieveAssigneesDataForIssueWriter(ctx *context.Context) {
+	var err error
+	d.AssigneesData.CandidateAssignees, err = repo_model.GetRepoAssignees(ctx, d.Repository)
 	if err != nil {
 		ctx.ServerError("GetRepoAssignees", err)
 		return
 	}
-	ctx.Data["Assignees"] = shared_user.MakeSelfOnTop(ctx.Doer, assigneeUsers)
-
+	d.AssigneesData.CandidateAssignees = shared_user.MakeSelfOnTop(ctx.Doer, d.AssigneesData.CandidateAssignees)
+	if d.Issue != nil {
+		_ = d.Issue.LoadAssignees(ctx)
+		ids := make([]string, 0, len(d.Issue.Assignees))
+		for _, a := range d.Issue.Assignees {
+			ids = append(ids, strconv.FormatInt(a.ID, 10))
+		}
+		d.AssigneesData.SelectedAssigneeIDs = strings.Join(ids, ",")
+	}
+	// FIXME: this is a tricky part which writes ctx.Data["Mentionable*"]
 	handleTeamMentions(ctx)
 }
 
-func retrieveProjects(ctx *context.Context, repo *repo_model.Repository) {
+func retrieveProjectsForIssueList(ctx *context.Context, repo *repo_model.Repository) {
+	ctx.Data["OpenProjects"], ctx.Data["ClosedProjects"] = retrieveProjectsInternal(ctx, repo)
+}
+
+type issueSidebarProjectsData struct {
+	SelectedProjectID int64
+	OpenProjects      []*project_model.Project
+	ClosedProjects    []*project_model.Project
+}
+
+func (d *IssuePageMetaData) retrieveProjectsDataForIssueWriter(ctx *context.Context) {
+	if d.Issue != nil && d.Issue.Project != nil {
+		d.ProjectsData.SelectedProjectID = d.Issue.Project.ID
+	}
+	d.ProjectsData.OpenProjects, d.ProjectsData.ClosedProjects = retrieveProjectsInternal(ctx, ctx.Repo.Repository)
+}
+
+func retrieveProjectsInternal(ctx *context.Context, repo *repo_model.Repository) (open, closed []*project_model.Project) {
 	// Distinguish whether the owner of the repository
 	// is an individual or an organization
 	repoOwnerType := project_model.TypeIndividual
@@ -609,7 +719,7 @@ func retrieveProjects(ctx *context.Context, repo *repo_model.Repository) {
 		})
 		if err != nil {
 			ctx.ServerError("GetProjects", err)
-			return
+			return nil, nil
 		}
 		closedProjects, err = db.Find[project_model.Project](ctx, project_model.SearchOptions{
 			ListOptions: db.ListOptionsAll,
@@ -619,7 +729,7 @@ func retrieveProjects(ctx *context.Context, repo *repo_model.Repository) {
 		})
 		if err != nil {
 			ctx.ServerError("GetProjects", err)
-			return
+			return nil, nil
 		}
 	}
 
@@ -632,7 +742,7 @@ func retrieveProjects(ctx *context.Context, repo *repo_model.Repository) {
 		})
 		if err != nil {
 			ctx.ServerError("GetProjects", err)
-			return
+			return nil, nil
 		}
 		openProjects = append(openProjects, openProjects2...)
 		closedProjects2, err := db.Find[project_model.Project](ctx, project_model.SearchOptions{
@@ -643,13 +753,11 @@ func retrieveProjects(ctx *context.Context, repo *repo_model.Repository) {
 		})
 		if err != nil {
 			ctx.ServerError("GetProjects", err)
-			return
+			return nil, nil
 		}
 		closedProjects = append(closedProjects, closedProjects2...)
 	}
-
-	ctx.Data["OpenProjects"] = openProjects
-	ctx.Data["ClosedProjects"] = closedProjects
+	return openProjects, closedProjects
 }
 
 // repoReviewerSelection items to bee shown
@@ -665,10 +773,6 @@ type repoReviewerSelection struct {
 }
 
 type issueSidebarReviewersData struct {
-	Repository           *repo_model.Repository
-	RepoOwnerName        string
-	RepoLink             string
-	IssueID              int64
 	CanChooseReviewer    bool
 	OriginalReviews      issues_model.ReviewList
 	TeamReviewers        []*repoReviewerSelection
@@ -677,41 +781,44 @@ type issueSidebarReviewersData struct {
 }
 
 // RetrieveRepoReviewers find all reviewers of a repository. If issue is nil, it means the doer is creating a new PR.
-func RetrieveRepoReviewers(ctx *context.Context, repo *repo_model.Repository, issue *issues_model.Issue, canChooseReviewer bool) {
-	data := &issueSidebarReviewersData{}
-	data.RepoLink = ctx.Repo.RepoLink
-	data.Repository = repo
-	data.RepoOwnerName = repo.OwnerName
-	data.CanChooseReviewer = canChooseReviewer
+func (d *IssuePageMetaData) retrieveReviewersData(ctx *context.Context) {
+	data := d.ReviewersData
+	repo := d.Repository
+	if ctx.Doer != nil && ctx.IsSigned {
+		if d.Issue == nil {
+			data.CanChooseReviewer = true
+		} else {
+			data.CanChooseReviewer = issue_service.CanDoerChangeReviewRequests(ctx, ctx.Doer, repo, d.Issue)
+		}
+	}
 
 	var posterID int64
 	var isClosed bool
 	var reviews issues_model.ReviewList
 
-	if issue == nil {
+	if d.Issue == nil {
 		posterID = ctx.Doer.ID
 	} else {
-		posterID = issue.PosterID
-		if issue.OriginalAuthorID > 0 {
+		posterID = d.Issue.PosterID
+		if d.Issue.OriginalAuthorID > 0 {
 			posterID = 0 // for migrated PRs, no poster ID
 		}
 
-		data.IssueID = issue.ID
-		isClosed = issue.IsClosed || issue.PullRequest.HasMerged
+		isClosed = d.Issue.IsClosed || d.Issue.PullRequest.HasMerged
 
-		originalAuthorReviews, err := issues_model.GetReviewersFromOriginalAuthorsByIssueID(ctx, issue.ID)
+		originalAuthorReviews, err := issues_model.GetReviewersFromOriginalAuthorsByIssueID(ctx, d.Issue.ID)
 		if err != nil {
 			ctx.ServerError("GetReviewersFromOriginalAuthorsByIssueID", err)
 			return
 		}
 		data.OriginalReviews = originalAuthorReviews
 
-		reviews, err = issues_model.GetReviewsByIssueID(ctx, issue.ID)
+		reviews, err = issues_model.GetReviewsByIssueID(ctx, d.Issue.ID)
 		if err != nil {
 			ctx.ServerError("GetReviewersByIssueID", err)
 			return
 		}
-		if len(reviews) == 0 && !canChooseReviewer {
+		if len(reviews) == 0 && !data.CanChooseReviewer {
 			return
 		}
 	}
@@ -724,7 +831,7 @@ func RetrieveRepoReviewers(ctx *context.Context, repo *repo_model.Repository, is
 		reviewers           []*user_model.User
 	)
 
-	if canChooseReviewer {
+	if data.CanChooseReviewer {
 		var err error
 		reviewers, err = repo_model.GetReviewers(ctx, repo, ctx.Doer.ID, posterID)
 		if err != nil {
@@ -760,7 +867,7 @@ func RetrieveRepoReviewers(ctx *context.Context, repo *repo_model.Repository, is
 			tmp.ItemID = -review.ReviewerTeamID
 		}
 
-		if canChooseReviewer {
+		if data.CanChooseReviewer {
 			// Users who can choose reviewers can also remove review requests
 			tmp.CanChange = true
 		} else if ctx.Doer != nil && ctx.Doer.ID == review.ReviewerID && review.Type == issues_model.ReviewTypeRequest {
@@ -770,7 +877,7 @@ func RetrieveRepoReviewers(ctx *context.Context, repo *repo_model.Repository, is
 
 		pullReviews = append(pullReviews, tmp)
 
-		if canChooseReviewer {
+		if data.CanChooseReviewer {
 			if tmp.IsTeam {
 				teamReviewersResult = append(teamReviewersResult, tmp)
 			} else {
@@ -811,7 +918,7 @@ func RetrieveRepoReviewers(ctx *context.Context, repo *repo_model.Repository, is
 		data.CurrentPullReviewers = currentPullReviewers
 	}
 
-	if canChooseReviewer && reviewersResult != nil {
+	if data.CanChooseReviewer && reviewersResult != nil {
 		preadded := len(reviewersResult)
 		for _, reviewer := range reviewers {
 			found := false
@@ -839,7 +946,7 @@ func RetrieveRepoReviewers(ctx *context.Context, repo *repo_model.Repository, is
 		data.Reviewers = reviewersResult
 	}
 
-	if canChooseReviewer && teamReviewersResult != nil {
+	if data.CanChooseReviewer && teamReviewersResult != nil {
 		preadded := len(teamReviewersResult)
 		for _, team := range teamReviewers {
 			found := false
@@ -866,15 +973,9 @@ func RetrieveRepoReviewers(ctx *context.Context, repo *repo_model.Repository, is
 
 		data.TeamReviewers = teamReviewersResult
 	}
-
-	ctx.Data["IssueSidebarReviewersData"] = data
 }
 
 type issueSidebarLabelsData struct {
-	Repository       *repo_model.Repository
-	RepoLink         string
-	IssueID          int64
-	IsPullRequest    bool
 	AllLabels        []*issues_model.Label
 	RepoLabels       []*issues_model.Label
 	OrgLabels        []*issues_model.Label
@@ -922,60 +1023,30 @@ func (d *issueSidebarLabelsData) SetSelectedLabelIDs(labelIDs []int64) {
 	)
 }
 
-func retrieveRepoLabels(ctx *context.Context, repo *repo_model.Repository, issueID int64, isPull bool) *issueSidebarLabelsData {
-	labelsData := &issueSidebarLabelsData{
-		Repository:    repo,
-		RepoLink:      ctx.Repo.RepoLink,
-		IssueID:       issueID,
-		IsPullRequest: isPull,
-	}
-	ctx.Data["IssueSidebarLabelsData"] = labelsData
+func (d *IssuePageMetaData) retrieveLabelsData(ctx *context.Context) {
+	repo := d.Repository
+	labelsData := d.LabelsData
 
 	labels, err := issues_model.GetLabelsByRepoID(ctx, repo.ID, "", db.ListOptions{})
 	if err != nil {
 		ctx.ServerError("GetLabelsByRepoID", err)
-		return nil
+		return
 	}
 	labelsData.RepoLabels = labels
 
 	if repo.Owner.IsOrganization() {
 		orgLabels, err := issues_model.GetLabelsByOrgID(ctx, repo.Owner.ID, ctx.FormString("sort"), db.ListOptions{})
 		if err != nil {
-			return nil
+			return
 		}
 		labelsData.OrgLabels = orgLabels
 	}
 	labelsData.AllLabels = append(labelsData.AllLabels, labelsData.RepoLabels...)
 	labelsData.AllLabels = append(labelsData.AllLabels, labelsData.OrgLabels...)
-	return labelsData
-}
-
-// retrieveRepoMetasForIssueWriter finds some the meta information of a repository for an issue/pr writer
-func retrieveRepoMetasForIssueWriter(ctx *context.Context, repo *repo_model.Repository, isPull bool) {
-	if !ctx.Repo.CanWriteIssuesOrPulls(isPull) {
-		return
-	}
-
-	RetrieveRepoMilestonesAndAssignees(ctx, repo)
-	if ctx.Written() {
-		return
-	}
-
-	retrieveProjects(ctx, repo)
-	if ctx.Written() {
-		return
-	}
-
-	PrepareBranchList(ctx)
-	if ctx.Written() {
-		return
-	}
-	// Contains true if the user can create issue dependencies
-	ctx.Data["CanCreateIssueDependencies"] = ctx.Repo.CanCreateIssueDependencies(ctx, ctx.Doer, isPull)
 }
 
 // Tries to load and set an issue template. The first return value indicates if a template was loaded.
-func setTemplateIfExists(ctx *context.Context, ctxDataKey string, possibleFiles []string, labelsData *issueSidebarLabelsData) (bool, map[string]error) {
+func setTemplateIfExists(ctx *context.Context, ctxDataKey string, possibleFiles []string, metaData *IssuePageMetaData) (bool, map[string]error) {
 	commit, err := ctx.Repo.GitRepo.GetBranchCommit(ctx.Repo.Repository.DefaultBranch)
 	if err != nil {
 		return false, nil
@@ -1013,24 +1084,20 @@ func setTemplateIfExists(ctx *context.Context, ctxDataKey string, possibleFiles
 			ctx.Data["TemplateFile"] = template.FileName
 		}
 
-		labelsData.SetSelectedLabelNames(template.Labels)
+		metaData.LabelsData.SetSelectedLabelNames(template.Labels)
 
-		selectedAssigneeIDs := make([]int64, 0, len(template.Assignees))
 		selectedAssigneeIDStrings := make([]string, 0, len(template.Assignees))
-		if userIDs, err := user_model.GetUserIDsByNames(ctx, template.Assignees, false); err == nil {
+		if userIDs, err := user_model.GetUserIDsByNames(ctx, template.Assignees, true); err == nil {
 			for _, userID := range userIDs {
-				selectedAssigneeIDs = append(selectedAssigneeIDs, userID)
 				selectedAssigneeIDStrings = append(selectedAssigneeIDStrings, strconv.FormatInt(userID, 10))
 			}
 		}
+		metaData.AssigneesData.SelectedAssigneeIDs = strings.Join(selectedAssigneeIDStrings, ",")
 
 		if template.Ref != "" && !strings.HasPrefix(template.Ref, "refs/") { // Assume that the ref intended is always a branch - for tags users should use refs/tags/<ref>
 			template.Ref = git.BranchPrefix + template.Ref
 		}
 
-		ctx.Data["HasSelectedAssignee"] = len(selectedAssigneeIDs) > 0
-		ctx.Data["assignee_ids"] = strings.Join(selectedAssigneeIDStrings, ",")
-		ctx.Data["SelectedAssigneeIDs"] = selectedAssigneeIDs
 		ctx.Data["Reference"] = template.Ref
 		ctx.Data["RefEndName"] = git.RefName(template.Ref).ShortName()
 		return true, templateErrs
@@ -1057,42 +1124,19 @@ func NewIssue(ctx *context.Context) {
 	ctx.Data["IsAttachmentEnabled"] = setting.Attachment.Enabled
 	upload.AddUploadContext(ctx, "comment")
 
-	milestoneID := ctx.FormInt64("milestone")
-	if milestoneID > 0 {
-		milestone, err := issues_model.GetMilestoneByRepoID(ctx, ctx.Repo.Repository.ID, milestoneID)
-		if err != nil {
-			log.Error("GetMilestoneByID: %d: %v", milestoneID, err)
-		} else {
-			ctx.Data["milestone_id"] = milestoneID
-			ctx.Data["Milestone"] = milestone
-		}
+	pageMetaData := retrieveRepoIssueMetaData(ctx, ctx.Repo.Repository, nil, false)
+	if ctx.Written() {
+		return
 	}
 
-	projectID := ctx.FormInt64("project")
-	if projectID > 0 && isProjectsEnabled {
-		project, err := project_model.GetProjectByID(ctx, projectID)
-		if err != nil {
-			log.Error("GetProjectByID: %d: %v", projectID, err)
-		} else if project.RepoID != ctx.Repo.Repository.ID {
-			log.Error("GetProjectByID: %d: %v", projectID, fmt.Errorf("project[%d] not in repo [%d]", project.ID, ctx.Repo.Repository.ID))
-		} else {
-			ctx.Data["project_id"] = projectID
-			ctx.Data["Project"] = project
-		}
-
+	pageMetaData.MilestonesData.SelectedMilestoneID = ctx.FormInt64("milestone")
+	pageMetaData.ProjectsData.SelectedProjectID = ctx.FormInt64("project")
+	if pageMetaData.ProjectsData.SelectedProjectID > 0 {
 		if len(ctx.Req.URL.Query().Get("project")) > 0 {
 			ctx.Data["redirect_after_creation"] = "project"
 		}
 	}
 
-	retrieveRepoMetasForIssueWriter(ctx, ctx.Repo.Repository, false)
-	if ctx.Written() {
-		return
-	}
-	labelsData := retrieveRepoLabels(ctx, ctx.Repo.Repository, 0, false)
-	if ctx.Written() {
-		return
-	}
 	tags, err := repo_model.GetTagNamesByRepoID(ctx, ctx.Repo.Repository.ID)
 	if err != nil {
 		ctx.ServerError("GetTagNamesByRepoID", err)
@@ -1101,7 +1145,7 @@ func NewIssue(ctx *context.Context) {
 	ctx.Data["Tags"] = tags
 
 	ret := issue_service.ParseTemplatesFromDefaultBranch(ctx.Repo.Repository, ctx.Repo.GitRepo)
-	templateLoaded, errs := setTemplateIfExists(ctx, issueTemplateKey, IssueTemplateCandidates, labelsData)
+	templateLoaded, errs := setTemplateIfExists(ctx, issueTemplateKey, IssueTemplateCandidates, pageMetaData)
 	for k, v := range errs {
 		ret.TemplateErrors[k] = v
 	}
@@ -1196,8 +1240,16 @@ func DeleteIssue(ctx *context.Context) {
 	ctx.Redirect(fmt.Sprintf("%s/issues", ctx.Repo.Repository.Link()), http.StatusSeeOther)
 }
 
-// ValidateRepoMetas check and returns repository's meta information
-func ValidateRepoMetas(ctx *context.Context, form forms.CreateIssueForm, isPull bool) (ret struct {
+func toSet[ItemType any, KeyType comparable](slice []ItemType, keyFunc func(ItemType) KeyType) container.Set[KeyType] {
+	s := make(container.Set[KeyType])
+	for _, item := range slice {
+		s.Add(keyFunc(item))
+	}
+	return s
+}
+
+// ValidateRepoMetasForNewIssue check and returns repository's meta information
+func ValidateRepoMetasForNewIssue(ctx *context.Context, form forms.CreateIssueForm, isPull bool) (ret struct {
 	LabelIDs, AssigneeIDs  []int64
 	MilestoneID, ProjectID int64
 
@@ -1205,126 +1257,76 @@ func ValidateRepoMetas(ctx *context.Context, form forms.CreateIssueForm, isPull
 	TeamReviewers []*organization.Team
 },
 ) {
-	var (
-		repo = ctx.Repo.Repository
-		err  error
-	)
-
-	retrieveRepoMetasForIssueWriter(ctx, ctx.Repo.Repository, isPull)
-	if ctx.Written() {
-		return ret
-	}
-	labelsData := retrieveRepoLabels(ctx, ctx.Repo.Repository, 0, isPull)
+	pageMetaData := retrieveRepoIssueMetaData(ctx, ctx.Repo.Repository, nil, isPull)
 	if ctx.Written() {
 		return ret
 	}
 
-	var labelIDs []int64
-	// Check labels.
-	if len(form.LabelIDs) > 0 {
-		labelIDs, err = base.StringsToInt64s(strings.Split(form.LabelIDs, ","))
-		if err != nil {
-			return ret
-		}
-		labelsData.SetSelectedLabelIDs(labelIDs)
-	}
-
-	// Check milestone.
-	milestoneID := form.MilestoneID
-	if milestoneID > 0 {
-		milestone, err := issues_model.GetMilestoneByRepoID(ctx, ctx.Repo.Repository.ID, milestoneID)
-		if err != nil {
-			ctx.ServerError("GetMilestoneByID", err)
-			return ret
-		}
-		if milestone.RepoID != repo.ID {
-			ctx.ServerError("GetMilestoneByID", err)
-			return ret
-		}
-		ctx.Data["Milestone"] = milestone
-		ctx.Data["milestone_id"] = milestoneID
+	inputLabelIDs, _ := base.StringsToInt64s(strings.Split(form.LabelIDs, ","))
+	candidateLabels := toSet(pageMetaData.LabelsData.AllLabels, func(label *issues_model.Label) int64 { return label.ID })
+	if len(inputLabelIDs) > 0 && !candidateLabels.Contains(inputLabelIDs...) {
+		ctx.NotFound("", nil)
+		return ret
 	}
+	pageMetaData.LabelsData.SetSelectedLabelIDs(inputLabelIDs)
 
-	if form.ProjectID > 0 {
-		p, err := project_model.GetProjectByID(ctx, form.ProjectID)
-		if err != nil {
-			ctx.ServerError("GetProjectByID", err)
-			return ret
-		}
-		if p.RepoID != ctx.Repo.Repository.ID && p.OwnerID != ctx.Repo.Repository.OwnerID {
-			ctx.NotFound("", nil)
-			return ret
-		}
-
-		ctx.Data["Project"] = p
-		ctx.Data["project_id"] = form.ProjectID
+	allMilestones := append(slices.Clone(pageMetaData.MilestonesData.OpenMilestones), pageMetaData.MilestonesData.ClosedMilestones...)
+	candidateMilestones := toSet(allMilestones, func(milestone *issues_model.Milestone) int64 { return milestone.ID })
+	if form.MilestoneID > 0 && !candidateMilestones.Contains(form.MilestoneID) {
+		ctx.NotFound("", nil)
+		return ret
 	}
+	pageMetaData.MilestonesData.SelectedMilestoneID = form.MilestoneID
 
-	// Check assignees
-	var assigneeIDs []int64
-	if len(form.AssigneeIDs) > 0 {
-		assigneeIDs, err = base.StringsToInt64s(strings.Split(form.AssigneeIDs, ","))
-		if err != nil {
-			return ret
-		}
-
-		// Check if the passed assignees actually exists and is assignable
-		for _, aID := range assigneeIDs {
-			assignee, err := user_model.GetUserByID(ctx, aID)
-			if err != nil {
-				ctx.ServerError("GetUserByID", err)
-				return ret
-			}
-
-			valid, err := access_model.CanBeAssigned(ctx, assignee, repo, isPull)
-			if err != nil {
-				ctx.ServerError("CanBeAssigned", err)
-				return ret
-			}
-
-			if !valid {
-				ctx.ServerError("canBeAssigned", repo_model.ErrUserDoesNotHaveAccessToRepo{UserID: aID, RepoName: repo.Name})
-				return ret
-			}
-		}
+	allProjects := append(slices.Clone(pageMetaData.ProjectsData.OpenProjects), pageMetaData.ProjectsData.ClosedProjects...)
+	candidateProjects := toSet(allProjects, func(project *project_model.Project) int64 { return project.ID })
+	if form.ProjectID > 0 && !candidateProjects.Contains(form.ProjectID) {
+		ctx.NotFound("", nil)
+		return ret
 	}
+	pageMetaData.ProjectsData.SelectedProjectID = form.ProjectID
 
-	// Keep the old assignee id thingy for compatibility reasons
-	if form.AssigneeID > 0 {
-		assigneeIDs = append(assigneeIDs, form.AssigneeID)
+	candidateAssignees := toSet(pageMetaData.AssigneesData.CandidateAssignees, func(user *user_model.User) int64 { return user.ID })
+	inputAssigneeIDs, _ := base.StringsToInt64s(strings.Split(form.AssigneeIDs, ","))
+	if len(inputAssigneeIDs) > 0 && !candidateAssignees.Contains(inputAssigneeIDs...) {
+		ctx.NotFound("", nil)
+		return ret
 	}
+	pageMetaData.AssigneesData.SelectedAssigneeIDs = form.AssigneeIDs
 
-	// Check reviewers
+	// Check if the passed reviewers (user/team) actually exist
 	var reviewers []*user_model.User
 	var teamReviewers []*organization.Team
-	if isPull && len(form.ReviewerIDs) > 0 {
-		reviewerIDs, err := base.StringsToInt64s(strings.Split(form.ReviewerIDs, ","))
-		if err != nil {
-			return ret
+	reviewerIDs, _ := base.StringsToInt64s(strings.Split(form.ReviewerIDs, ","))
+	if isPull && len(reviewerIDs) > 0 {
+		userReviewersMap := map[int64]*user_model.User{}
+		teamReviewersMap := map[int64]*organization.Team{}
+		for _, r := range pageMetaData.ReviewersData.Reviewers {
+			userReviewersMap[r.User.ID] = r.User
+		}
+		for _, r := range pageMetaData.ReviewersData.TeamReviewers {
+			teamReviewersMap[r.Team.ID] = r.Team
 		}
-		// Check if the passed reviewers (user/team) actually exist
 		for _, rID := range reviewerIDs {
-			// negative reviewIDs represent team requests
-			if rID < 0 {
-				teamReviewer, err := organization.GetTeamByID(ctx, -rID)
-				if err != nil {
-					ctx.ServerError("GetTeamByID", err)
+			if rID < 0 { // negative reviewIDs represent team requests
+				team, ok := teamReviewersMap[-rID]
+				if !ok {
+					ctx.NotFound("", nil)
 					return ret
 				}
-				teamReviewers = append(teamReviewers, teamReviewer)
-				continue
-			}
-
-			reviewer, err := user_model.GetUserByID(ctx, rID)
-			if err != nil {
-				ctx.ServerError("GetUserByID", err)
-				return ret
+				teamReviewers = append(teamReviewers, team)
+			} else {
+				user, ok := userReviewersMap[rID]
+				if !ok {
+					ctx.NotFound("", nil)
+					return ret
+				}
+				reviewers = append(reviewers, user)
 			}
-			reviewers = append(reviewers, reviewer)
 		}
 	}
 
-	ret.LabelIDs, ret.AssigneeIDs, ret.MilestoneID, ret.ProjectID = labelIDs, assigneeIDs, milestoneID, form.ProjectID
+	ret.LabelIDs, ret.AssigneeIDs, ret.MilestoneID, ret.ProjectID = inputLabelIDs, inputAssigneeIDs, form.MilestoneID, form.ProjectID
 	ret.Reviewers, ret.TeamReviewers = reviewers, teamReviewers
 	return ret
 }
@@ -1344,7 +1346,7 @@ func NewIssuePost(ctx *context.Context) {
 		attachments []string
 	)
 
-	validateRet := ValidateRepoMetas(ctx, *form, false)
+	validateRet := ValidateRepoMetasForNewIssue(ctx, *form, false)
 	if ctx.Written() {
 		return
 	}
@@ -1619,37 +1621,11 @@ func ViewIssue(ctx *context.Context) {
 		}
 	}
 
-	retrieveRepoMetasForIssueWriter(ctx, repo, issue.IsPull)
+	pageMetaData := retrieveRepoIssueMetaData(ctx, repo, issue, issue.IsPull)
 	if ctx.Written() {
 		return
 	}
-	labelsData := retrieveRepoLabels(ctx, repo, issue.ID, issue.IsPull)
-	if ctx.Written() {
-		return
-	}
-	labelsData.SetSelectedLabels(issue.Labels)
-
-	// Check milestone and assignee.
-	if ctx.Repo.CanWriteIssuesOrPulls(issue.IsPull) {
-		RetrieveRepoMilestonesAndAssignees(ctx, repo)
-		retrieveProjects(ctx, repo)
-
-		if ctx.Written() {
-			return
-		}
-	}
-
-	if issue.IsPull {
-		canChooseReviewer := false
-		if ctx.Doer != nil && ctx.IsSigned {
-			canChooseReviewer = issue_service.CanDoerChangeReviewRequests(ctx, ctx.Doer, repo, issue)
-		}
-
-		RetrieveRepoReviewers(ctx, repo, issue, canChooseReviewer)
-		if ctx.Written() {
-			return
-		}
-	}
+	pageMetaData.LabelsData.SetSelectedLabels(issue.Labels)
 
 	if ctx.IsSigned {
 		// Update issue-user.

routers/web/repo/pull.go

@@ -1269,7 +1269,7 @@ func CompareAndPullRequestPost(ctx *context.Context) {
 		return
 	}
 
-	validateRet := ValidateRepoMetas(ctx, *form, true)
+	validateRet := ValidateRepoMetasForNewIssue(ctx, *form, true)
 	if ctx.Written() {
 		return
 	}

services/forms/repo_form.go

@@ -451,7 +451,6 @@ type CreateIssueForm struct {
 	Ref                 string `form:"ref"`
 	MilestoneID         int64
 	ProjectID           int64
-	AssigneeID          int64
 	Content             string
 	Files               []string
 	AllowMaintainerEdit bool

templates/repo/issue/milestone/select_menu.tmpl

@@ -1,38 +0,0 @@
-{{if or .OpenMilestones .ClosedMilestones}}
-	<div class="ui icon search input">
-		<i class="icon">{{svg "octicon-search" 16}}</i>
-		<input type="text" placeholder="{{ctx.Locale.Tr "repo.issues.filter_milestones"}}">
-	</div>
-	<div class="divider"></div>
-{{end}}
-<div class="no-select item">{{ctx.Locale.Tr "repo.issues.new.clear_milestone"}}</div>
-{{if and (not .OpenMilestones) (not .ClosedMilestones)}}
-	<div class="disabled item">
-		{{ctx.Locale.Tr "repo.issues.new.no_items"}}
-	</div>
-{{else}}
-	{{if .OpenMilestones}}
-		<div class="divider"></div>
-		<div class="header">
-			{{ctx.Locale.Tr "repo.issues.new.open_milestone"}}
-		</div>
-		{{range .OpenMilestones}}
-			<a class="item" data-id="{{.ID}}" data-href="{{$.RepoLink}}/issues?milestone={{.ID}}">
-				{{svg "octicon-milestone" 16 "tw-mr-1"}}
-				{{.Name}}
-			</a>
-		{{end}}
-	{{end}}
-	{{if .ClosedMilestones}}
-		<div class="divider"></div>
-		<div class="header">
-			{{ctx.Locale.Tr "repo.issues.new.closed_milestone"}}
-		</div>
-		{{range .ClosedMilestones}}
-			<a class="item" data-id="{{.ID}}" data-href="{{$.RepoLink}}/issues?milestone={{.ID}}">
-				{{svg "octicon-milestone" 16 "tw-mr-1"}}
-				{{.Name}}
-			</a>
-		{{end}}
-	{{end}}
-{{end}}

templates/repo/issue/new_form.tmpl

@@ -49,142 +49,22 @@
 	<div class="issue-content-right ui segment">
 		{{template "repo/issue/branch_selector_field" $}}
 		{{if .PageIsComparePull}}
-			{{template "repo/issue/sidebar/reviewer_list" $.IssueSidebarReviewersData}}
+			{{template "repo/issue/sidebar/reviewer_list" $.IssuePageMetaData}}
 			<div class="divider"></div>
 		{{end}}
 
-		{{template "repo/issue/sidebar/label_list" $.IssueSidebarLabelsData}}
-
-		<div class="divider"></div>
-
-		<input id="milestone_id" name="milestone_id" type="hidden" value="{{.milestone_id}}">
-		<div class="ui {{if not .HasIssuesOrPullsWritePermission}}disabled{{end}} floating jump select-milestone dropdown">
-			<span class="text flex-text-block">
-				<strong>{{ctx.Locale.Tr "repo.issues.new.milestone"}}</strong>
-				{{if .HasIssuesOrPullsWritePermission}}
-					{{svg "octicon-gear" 16 "tw-ml-1"}}
-				{{end}}
-			</span>
-			<div class="menu">
-				{{template "repo/issue/milestone/select_menu" .}}
-			</div>
-		</div>
-		<div class="ui select-milestone list">
-			<span class="no-select item {{if .Milestone}}tw-hidden{{end}}">{{ctx.Locale.Tr "repo.issues.new.no_milestone"}}</span>
-			<div class="selected">
-				{{if .Milestone}}
-					<a class="item muted sidebar-item-link" href="{{.RepoLink}}/issues?milestone={{.Milestone.ID}}">
-						{{svg "octicon-milestone" 18 "tw-mr-2"}}
-						{{.Milestone.Name}}
-					</a>
-				{{end}}
-			</div>
-		</div>
-
+		{{template "repo/issue/sidebar/label_list" $.IssuePageMetaData}}
+		{{template "repo/issue/sidebar/milestone_list" $.IssuePageMetaData}}
 		{{if .IsProjectsEnabled}}
-		<div class="divider"></div>
-
-		<input id="project_id" name="project_id" type="hidden" value="{{.project_id}}">
-		<div class="ui {{if not .HasIssuesOrPullsWritePermission}}disabled{{end}} floating jump select-project dropdown">
-			<span class="text flex-text-block">
-				<strong>{{ctx.Locale.Tr "repo.issues.new.projects"}}</strong>
-				{{if .HasIssuesOrPullsWritePermission}}
-					{{svg "octicon-gear" 16 "tw-ml-1"}}
-				{{end}}
-			</span>
-			<div class="menu">
-				{{if or .OpenProjects .ClosedProjects}}
-				<div class="ui icon search input">
-					<i class="icon">{{svg "octicon-search" 16}}</i>
-					<input type="text" placeholder="{{ctx.Locale.Tr "repo.issues.filter_projects"}}">
-				</div>
-				{{end}}
-				<div class="no-select item">{{ctx.Locale.Tr "repo.issues.new.clear_projects"}}</div>
-				{{if and (not .OpenProjects) (not .ClosedProjects)}}
-					<div class="disabled item">
-						{{ctx.Locale.Tr "repo.issues.new.no_items"}}
-					</div>
-				{{else}}
-					{{if .OpenProjects}}
-						<div class="divider"></div>
-						<div class="header">
-							{{ctx.Locale.Tr "repo.issues.new.open_projects"}}
-						</div>
-						{{range .OpenProjects}}
-							<a class="item muted sidebar-item-link" data-id="{{.ID}}" data-href="{{.Link ctx}}">
-								{{svg .IconName 18 "tw-mr-2"}}{{.Title}}
-							</a>
-						{{end}}
-					{{end}}
-					{{if .ClosedProjects}}
-						<div class="divider"></div>
-						<div class="header">
-							{{ctx.Locale.Tr "repo.issues.new.closed_projects"}}
-						</div>
-						{{range .ClosedProjects}}
-							<a class="item muted sidebar-item-link" data-id="{{.ID}}" data-href="{{.Link ctx}}">
-								{{svg .IconName 18 "tw-mr-2"}}{{.Title}}
-							</a>
-						{{end}}
-					{{end}}
-				{{end}}
-			</div>
-		</div>
-		<div class="ui select-project list">
-			<span class="no-select item {{if .Project}}tw-hidden{{end}}">{{ctx.Locale.Tr "repo.issues.new.no_projects"}}</span>
-			<div class="selected">
-				{{if .Project}}
-					<a class="item muted sidebar-item-link" href="{{.Project.Link ctx}}">
-						{{svg .Project.IconName 18 "tw-mr-2"}}{{.Project.Title}}
-					</a>
-				{{end}}
-			</div>
-		</div>
+			{{template "repo/issue/sidebar/project_list" $.IssuePageMetaData}}
 		{{end}}
-		<div class="divider"></div>
-			<input id="assignee_ids" name="assignee_ids" type="hidden" value="{{.assignee_ids}}">
-			<div class="ui {{if not .HasIssuesOrPullsWritePermission}}disabled{{end}} floating jump select-assignees dropdown">
-				<span class="text flex-text-block">
-					<strong>{{ctx.Locale.Tr "repo.issues.new.assignees"}}</strong>
-					{{if .HasIssuesOrPullsWritePermission}}
-						{{svg "octicon-gear" 16 "tw-ml-1"}}
-					{{end}}
-				</span>
-				<div class="filter menu" data-id="#assignee_ids">
-					<div class="ui icon search input">
-						<i class="icon">{{svg "octicon-search" 16}}</i>
-						<input type="text" placeholder="{{ctx.Locale.Tr "repo.issues.filter_assignees"}}">
-					</div>
-					<div class="no-select item">{{ctx.Locale.Tr "repo.issues.new.clear_assignees"}}</div>
-					{{range .Assignees}}
-						<a class="{{if SliceUtils.Contains $.SelectedAssigneeIDs .ID}}checked{{end}} item muted" href="#" data-id="{{.ID}}" data-id-selector="#assignee_{{.ID}}">
-							<span class="octicon-check {{if not (SliceUtils.Contains $.SelectedAssigneeIDs .ID)}}tw-invisible{{end}}">{{svg "octicon-check"}}</span>
-							<span class="text">
-								{{ctx.AvatarUtils.Avatar . 28 "tw-mr-2"}}{{template "repo/search_name" .}}
-							</span>
-						</a>
-					{{end}}
-				</div>
-			</div>
-			<div class="ui assignees list">
-				<span class="no-select item {{if .HasSelectedAssignee}}tw-hidden{{end}}">
-					{{ctx.Locale.Tr "repo.issues.new.no_assignees"}}
-				</span>
-				<div class="selected">
-				{{range .Assignees}}
-					<a class="item tw-p-1 muted {{if not (SliceUtils.Contains $.SelectedAssigneeIDs .ID)}}tw-hidden{{end}}" id="assignee_{{.ID}}" href="{{$.RepoLink}}/issues?assignee={{.ID}}">
-						{{ctx.AvatarUtils.Avatar . 28 "tw-mr-2 tw-align-middle"}}{{.GetDisplayName}}
-					</a>
-				{{end}}
-				</div>
-			</div>
+		{{template "repo/issue/sidebar/assignee_list" $.IssuePageMetaData}}
+
 		{{if and .PageIsComparePull (not (eq .HeadRepo.FullName .BaseCompareRepo.FullName)) .CanWriteToHeadRepo}}
 			<div class="divider"></div>
-			<div class="inline field">
-				<div class="ui checkbox">
-					<label data-tooltip-content="{{ctx.Locale.Tr "repo.pulls.allow_edits_from_maintainers_desc"}}"><strong>{{ctx.Locale.Tr "repo.pulls.allow_edits_from_maintainers"}}</strong></label>
-					<input name="allow_maintainer_edit" type="checkbox" {{if .AllowMaintainerEdit}}checked{{end}}>
-				</div>
+			<div class="ui checkbox">
+				<label data-tooltip-content="{{ctx.Locale.Tr "repo.pulls.allow_edits_from_maintainers_desc"}}"><strong>{{ctx.Locale.Tr "repo.pulls.allow_edits_from_maintainers"}}</strong></label>
+				<input name="allow_maintainer_edit" type="checkbox" {{if .AllowMaintainerEdit}}checked{{end}}>
 			</div>
 		{{end}}
 	</div>

templates/repo/issue/sidebar/assignee_list.tmpl

@@ -1,46 +1,35 @@
+{{$pageMeta := .}}
+{{$data := .AssigneesData}}
+{{$issueAssignees := NIL}}{{if $pageMeta.Issue}}{{$issueAssignees = $pageMeta.Issue.Assignees}}{{end}}
 <div class="divider"></div>
-<input id="assignee_id" name="assignee_id" type="hidden" value="{{.assignee_id}}">
-<div class="ui {{if or (not .HasIssuesOrPullsWritePermission) .Repository.IsArchived}}disabled{{end}} floating jump select-assignees-modify dropdown">
-	<a class="text muted flex-text-block">
-		<strong>{{ctx.Locale.Tr "repo.issues.new.assignees"}}</strong>
-		{{if and .HasIssuesOrPullsWritePermission (not .Repository.IsArchived)}}
-			{{svg "octicon-gear" 16 "tw-ml-1"}}
-		{{end}}
-	</a>
-	<div class="filter menu" data-action="update" data-issue-id="{{$.Issue.ID}}" data-update-url="{{$.RepoLink}}/issues/assignee">
-		<div class="ui icon search input">
-			<i class="icon">{{svg "octicon-search" 16}}</i>
-			<input type="text" placeholder="{{ctx.Locale.Tr "repo.issues.filter_assignees"}}">
+<div class="issue-sidebar-combo" data-selection-mode="multiple" data-update-algo="diff"
+		{{if $pageMeta.Issue}}data-update-url="{{$pageMeta.RepoLink}}/issues/assignee?issue_ids={{$pageMeta.Issue.ID}}"{{end}}
+>
+	<input class="combo-value" name="assignee_ids" type="hidden" value="{{$data.SelectedAssigneeIDs}}">
+	<div class="ui dropdown {{if not $pageMeta.CanModifyIssueOrPull}}disabled{{end}}">
+		<a class="text muted">
+			<strong>{{ctx.Locale.Tr "repo.issues.new.assignees"}}</strong> {{if $pageMeta.CanModifyIssueOrPull}}{{svg "octicon-gear"}}{{end}}
+		</a>
+		<div class="menu">
+			<div class="ui icon search input">
+				<i class="icon">{{svg "octicon-search" 16}}</i>
+				<input type="text" placeholder="{{ctx.Locale.Tr "repo.issues.filter_assignees"}}">
+			</div>
+			<div class="item clear-selection">{{ctx.Locale.Tr "repo.issues.new.clear_assignees"}}</div>
+			{{range $data.CandidateAssignees}}
+				<a class="item muted" href="#" data-value="{{.ID}}">
+					<span class="item-check-mark">{{svg "octicon-check"}}</span>
+					{{ctx.AvatarUtils.Avatar . 20}} {{template "repo/search_name" .}}
+				</a>
+			{{end}}
 		</div>
-		<div class="no-select item">{{ctx.Locale.Tr "repo.issues.new.clear_assignees"}}</div>
-		{{range .Assignees}}
-
-			{{$AssigneeID := .ID}}
-			<a class="item{{range $.Issue.Assignees}}{{if eq .ID $AssigneeID}} checked{{end}}{{end}}" href="#" data-id="{{.ID}}" data-id-selector="#assignee_{{.ID}}">
-				{{$checked := false}}
-				{{range $.Issue.Assignees}}
-					{{if eq .ID $AssigneeID}}
-						{{$checked = true}}
-					{{end}}
-				{{end}}
-				<span class="octicon-check {{if not $checked}}tw-invisible{{end}}">{{svg "octicon-check"}}</span>
-				<span class="text">
-					{{ctx.AvatarUtils.Avatar . 20 "tw-mr-2"}}{{template "repo/search_name" .}}
-				</span>
-			</a>
-		{{end}}
 	</div>
-</div>
-<div class="ui assignees list">
-	<span class="no-select item {{if .Issue.Assignees}}tw-hidden{{end}}">{{ctx.Locale.Tr "repo.issues.new.no_assignees"}}</span>
-	<div class="selected">
-		{{range .Issue.Assignees}}
-			<div class="item">
-				<a class="muted sidebar-item-link" href="{{$.RepoLink}}/{{if $.Issue.IsPull}}pulls{{else}}issues{{end}}?assignee={{.ID}}">
-					{{ctx.AvatarUtils.Avatar . 28 "tw-mr-2"}}
-					{{.GetDisplayName}}
-				</a>
-			</div>
+	<div class="ui list tw-flex tw-flex-row tw-gap-2">
+		<span class="item empty-list {{if $issueAssignees}}tw-hidden{{end}}">{{ctx.Locale.Tr "repo.issues.new.no_assignees"}}</span>
+		{{range $issueAssignees}}
+			<a class="item muted" href="{{$pageMeta.RepoLink}}/{{if $pageMeta.IsPullRequest}}pulls{{else}}issues{{end}}?assignee={{.ID}}">
+					{{ctx.AvatarUtils.Avatar . 20}} {{.GetDisplayName}}
+			</a>
 		{{end}}
 	</div>
 </div>

templates/repo/issue/sidebar/label_list.tmpl

@@ -1,10 +1,12 @@
-{{$data := .}}
-{{$canChange := and ctx.RootData.HasIssuesOrPullsWritePermission (not $data.Repository.IsArchived)}}
-<div class="issue-sidebar-combo" {{if $data.IssueID}}data-update-url="{{$data.RepoLink}}/issues/labels?issue_ids={{$data.IssueID}}"{{end}}>
+{{$pageMeta := .}}
+{{$data := .LabelsData}}
+<div class="issue-sidebar-combo" data-selection-mode="multiple" data-update-algo="diff"
+		{{if $pageMeta.Issue}}data-update-url="{{$pageMeta.RepoLink}}/issues/labels?issue_ids={{$pageMeta.Issue.ID}}"{{end}}
+>
 	<input class="combo-value" name="label_ids" type="hidden" value="{{$data.SelectedLabelIDs}}">
-	<div class="ui dropdown {{if not $canChange}}disabled{{end}}">
+	<div class="ui dropdown {{if not $pageMeta.CanModifyIssueOrPull}}disabled{{end}}">
 		<a class="text muted">
-			<strong>{{ctx.Locale.Tr "repo.issues.new.labels"}}</strong> {{if $canChange}}{{svg "octicon-gear"}}{{end}}
+			<strong>{{ctx.Locale.Tr "repo.issues.new.labels"}}</strong> {{if $pageMeta.CanModifyIssueOrPull}}{{svg "octicon-gear"}}{{end}}
 		</a>
 		<div class="menu">
 			{{if not $data.AllLabels}}
@@ -16,7 +18,7 @@
 				</div>
 				<a class="item clear-selection" href="#">{{ctx.Locale.Tr "repo.issues.new.clear_labels"}}</a>
 				{{$previousExclusiveScope := "_no_scope"}}
-				{{range .RepoLabels}}
+				{{range $data.RepoLabels}}
 					{{$exclusiveScope := .ExclusiveScope}}
 					{{if and (ne $previousExclusiveScope "_no_scope") (ne $previousExclusiveScope $exclusiveScope)}}
 						<div class="divider"></div>
@@ -26,7 +28,7 @@
 				{{end}}
 				<div class="divider"></div>
 				{{$previousExclusiveScope = "_no_scope"}}
-				{{range .OrgLabels}}
+				{{range $data.OrgLabels}}
 					{{$exclusiveScope := .ExclusiveScope}}
 					{{if and (ne $previousExclusiveScope "_no_scope") (ne $previousExclusiveScope $exclusiveScope)}}
 						<div class="divider"></div>
@@ -42,7 +44,7 @@
 		<span class="item empty-list {{if $data.SelectedLabelIDs}}tw-hidden{{end}}">{{ctx.Locale.Tr "repo.issues.new.no_label"}}</span>
 		{{range $data.AllLabels}}
 			{{if .IsChecked}}
-				<a class="item" href="{{$data.RepoLink}}/{{if $data.IsPullRequest}}pulls{{else}}issues{{end}}?labels={{.ID}}">
+				<a class="item" href="{{$pageMeta.RepoLink}}/{{if $pageMeta.IsPullRequest}}pulls{{else}}issues{{end}}?labels={{.ID}}">
 					{{- ctx.RenderUtils.RenderLabel . -}}
 				</a>
 			{{end}}

templates/repo/issue/sidebar/label_list_item.tmpl

@@ -1,5 +1,5 @@
 {{$label := .Label}}
-<a class="item {{if $label.IsChecked}}checked{{else if $label.IsArchived}}tw-hidden{{end}}" href="#"
+<a class="item muted {{if $label.IsChecked}}checked{{else if $label.IsArchived}}tw-hidden{{end}}" href="#"
 	data-scope="{{$label.ExclusiveScope}}" data-value="{{$label.ID}}" {{if $label.IsArchived}}data-is-archived{{end}}
 >
 	<span class="item-check-mark">{{svg (Iif $label.ExclusiveScope "octicon-dot-fill" "octicon-check")}}</span>

templates/repo/issue/sidebar/milestone_list.tmpl

@@ -1,22 +1,52 @@
+{{$pageMeta := .}}
+{{$data := .MilestonesData}}
+{{$issueMilestone := NIL}}{{if and $pageMeta.Issue $pageMeta.Issue.Milestone}}{{$issueMilestone = $pageMeta.Issue.Milestone}}{{end}}
 <div class="divider"></div>
-<div class="ui {{if or (not .HasIssuesOrPullsWritePermission) .Repository.IsArchived}}disabled{{end}} floating jump select-milestone dropdown">
-	<a class="text muted flex-text-block">
-		<strong>{{ctx.Locale.Tr "repo.issues.new.milestone"}}</strong>
-		{{if and .HasIssuesOrPullsWritePermission (not .Repository.IsArchived)}}
-			{{svg "octicon-gear" 16 "tw-ml-1"}}
-		{{end}}
-	</a>
-	<div class="menu" data-action="update" data-issue-id="{{$.Issue.ID}}" data-update-url="{{$.RepoLink}}/issues/milestone">
-		{{template "repo/issue/milestone/select_menu" .}}
+<div class="issue-sidebar-combo" data-selection-mode="single" data-update-algo="all"
+		{{if $pageMeta.Issue}}data-update-url="{{$pageMeta.RepoLink}}/issues/milestone?issue_ids={{$pageMeta.Issue.ID}}"{{end}}
+>
+	<input class="combo-value" name="milestone_id" type="hidden" value="{{$data.SelectedMilestoneID}}">
+	<div class="ui dropdown {{if not $pageMeta.CanModifyIssueOrPull}}disabled{{end}} ">
+		<a class="text muted">
+			<strong>{{ctx.Locale.Tr "repo.issues.new.milestone"}}</strong> {{if $pageMeta.CanModifyIssueOrPull}}{{svg "octicon-gear"}}{{end}}
+		</a>
+		<div class="menu">
+			{{if and (not $data.OpenMilestones) (not $data.ClosedMilestones)}}
+				<div class="item disabled">{{ctx.Locale.Tr "repo.issues.new.no_items"}}</div>
+			{{else}}
+				<div class="ui icon search input">
+					<i class="icon">{{svg "octicon-search"}}</i>
+					<input type="text" placeholder="{{ctx.Locale.Tr "repo.issues.filter_milestones"}}">
+				</div>
+				<div class="divider"></div>
+				<div class="item clear-selection">{{ctx.Locale.Tr "repo.issues.new.clear_milestone"}}</div>
+				{{if $data.OpenMilestones}}
+					<div class="divider"></div>
+					<div class="header">{{ctx.Locale.Tr "repo.issues.new.open_milestone"}}</div>
+					{{range $data.OpenMilestones}}
+						<a class="item muted" data-value="{{.ID}}" href="{{$pageMeta.RepoLink}}/issues?milestone={{.ID}}">
+							{{svg "octicon-milestone" 18}} {{.Name}}
+						</a>
+					{{end}}
+				{{end}}
+				{{if $data.ClosedMilestones}}
+					<div class="divider"></div>
+					<div class="header">{{ctx.Locale.Tr "repo.issues.new.closed_milestone"}}</div>
+					{{range $data.ClosedMilestones}}
+						<a class="item muted" data-value="{{.ID}}" href="{{$pageMeta.RepoLink}}/issues?milestone={{.ID}}">
+							{{svg "octicon-milestone" 18}} {{.Name}}
+						</a>
+					{{end}}
+				{{end}}
+			{{end}}
+		</div>
 	</div>
-</div>
-<div class="ui select-milestone list">
-	<span class="no-select item {{if .Issue.Milestone}}tw-hidden{{end}}">{{ctx.Locale.Tr "repo.issues.new.no_milestone"}}</span>
-	<div class="selected">
-		{{if .Issue.Milestone}}
-			<a class="item muted sidebar-item-link" href="{{.RepoLink}}/milestone/{{.Issue.Milestone.ID}}">
-				{{svg "octicon-milestone" 18 "tw-mr-2"}}
-				{{.Issue.Milestone.Name}}
+
+	<div class="ui list">
+		<span class="item empty-list {{if $issueMilestone}}tw-hidden{{end}}">{{ctx.Locale.Tr "repo.issues.new.no_milestone"}}</span>
+		{{if $issueMilestone}}
+			<a class="item muted" href="{{$pageMeta.RepoLink}}/milestone/{{$issueMilestone.ID}}">
+				{{svg "octicon-milestone" 18}} {{$issueMilestone.Name}}
 			</a>
 		{{end}}
 	</div>

templates/repo/issue/sidebar/participant_list.tmpl

@@ -4,7 +4,7 @@
 	<div class="ui list tw-flex tw-flex-wrap">
 		{{range .Participants}}
 			<a {{if gt .ID 0}}href="{{.HomeLink}}"{{end}} data-tooltip-content="{{.GetDisplayName}}">
-				{{ctx.AvatarUtils.Avatar . 28 "tw-my-0.5 tw-mr-1"}}
+				{{ctx.AvatarUtils.Avatar . 20 "tw-my-0.5 tw-mr-1"}}
 			</a>
 		{{end}}
 	</div>

templates/repo/issue/sidebar/project_list.tmpl

@@ -1,53 +1,49 @@
-{{if .IsProjectsEnabled}}
-	<div class="divider"></div>
-
-	<div class="ui {{if or (not .HasIssuesOrPullsWritePermission) .Repository.IsArchived}}disabled{{end}} floating jump select-project dropdown">
-		<a class="text muted flex-text-block">
-			<strong>{{ctx.Locale.Tr "repo.issues.new.projects"}}</strong>
-			{{if and .HasIssuesOrPullsWritePermission (not .Repository.IsArchived)}}
-				{{svg "octicon-gear" 16 "tw-ml-1"}}
-			{{end}}
+{{$pageMeta := .}}
+{{$data := .ProjectsData}}
+{{$issueProject := NIL}}{{if and $pageMeta.Issue $pageMeta.Issue.Project}}{{$issueProject = $pageMeta.Issue.Project}}{{end}}
+<div class="divider"></div>
+<div class="issue-sidebar-combo" data-selection-mode="single" data-update-algo="all"
+		{{if $pageMeta.Issue}}data-update-url="{{$pageMeta.RepoLink}}/issues/projects?issue_ids={{$pageMeta.Issue.ID}}"{{end}}
+>
+	<input class="combo-value" name="project_id" type="hidden" value="{{$data.SelectedProjectID}}">
+	<div class="ui dropdown {{if not $pageMeta.CanModifyIssueOrPull}}disabled{{end}}">
+		<a class="text muted">
+			<strong>{{ctx.Locale.Tr "repo.issues.new.projects"}}</strong> {{if $pageMeta.CanModifyIssueOrPull}}{{svg "octicon-gear"}}{{end}}
 		</a>
-		<div class="menu" data-action="update" data-issue-id="{{$.Issue.ID}}" data-update-url="{{$.RepoLink}}/issues/projects">
-			{{if or .OpenProjects .ClosedProjects}}
+		<div class="menu">
+			{{if or $data.OpenProjects $data.ClosedProjects}}
 			<div class="ui icon search input">
 				<i class="icon">{{svg "octicon-search" 16}}</i>
 				<input type="text" placeholder="{{ctx.Locale.Tr "repo.issues.filter_projects"}}">
 			</div>
 			{{end}}
-			<div class="no-select item">{{ctx.Locale.Tr "repo.issues.new.clear_projects"}}</div>
-			{{if .OpenProjects}}
+			<div class="item clear-selection">{{ctx.Locale.Tr "repo.issues.new.clear_projects"}}</div>
+			{{if $data.OpenProjects}}
 				<div class="divider"></div>
-				<div class="header">
-					{{ctx.Locale.Tr "repo.issues.new.open_projects"}}
-				</div>
-				{{range .OpenProjects}}
-					<a class="item muted sidebar-item-link" data-id="{{.ID}}" data-href="{{.Link ctx}}">
-						{{svg .IconName 18 "tw-mr-2"}}{{.Title}}
+				<div class="header">{{ctx.Locale.Tr "repo.issues.new.open_projects"}}</div>
+				{{range $data.OpenProjects}}
+					<a class="item muted" data-value="{{.ID}}" href="{{.Link ctx}}">
+						{{svg .IconName 18}} {{.Title}}
 					</a>
 				{{end}}
 			{{end}}
-			{{if .ClosedProjects}}
+			{{if $data.ClosedProjects}}
 				<div class="divider"></div>
-				<div class="header">
-					{{ctx.Locale.Tr "repo.issues.new.closed_projects"}}
-				</div>
-				{{range .ClosedProjects}}
-					<a class="item muted sidebar-item-link" data-id="{{.ID}}" data-href="{{.Link ctx}}">
-						{{svg .IconName 18 "tw-mr-2"}}{{.Title}}
+				<div class="header">{{ctx.Locale.Tr "repo.issues.new.closed_projects"}}</div>
+				{{range $data.ClosedProjects}}
+					<a class="item muted" data-value="{{.ID}}" href="{{.Link ctx}}">
+						{{svg .IconName 18}} {{.Title}}
 					</a>
 				{{end}}
 			{{end}}
 		</div>
 	</div>
-	<div class="ui select-project list">
-		<span class="no-select item {{if .Issue.Project}}tw-hidden{{end}}">{{ctx.Locale.Tr "repo.issues.new.no_projects"}}</span>
-		<div class="selected">
-			{{if .Issue.Project}}
-				<a class="item muted sidebar-item-link" href="{{.Issue.Project.Link ctx}}">
-					{{svg .Issue.Project.IconName 18 "tw-mr-2"}}{{.Issue.Project.Title}}
-				</a>
-			{{end}}
-		</div>
+	<div class="ui list">
+		<span class="item empty-list {{if $issueProject}}tw-hidden{{end}}">{{ctx.Locale.Tr "repo.issues.new.no_projects"}}</span>
+		{{if $issueProject}}
+			<a class="item muted" href="{{$issueProject.Link ctx}}">
+				{{svg $issueProject.IconName 18}} {{$issueProject.Title}}
+			</a>
+		{{end}}
 	</div>
-{{end}}
+</div>

templates/repo/issue/sidebar/reviewer_list.tmpl

@@ -1,10 +1,14 @@
-{{$data := .}}
+{{$pageMeta := .}}
+{{$data := .ReviewersData}}
+{{$repoOwnerName := $pageMeta.Repository.OwnerName}}
 {{$hasCandidates := or $data.Reviewers $data.TeamReviewers}}
-<div class="issue-sidebar-combo" {{if $data.IssueID}}data-update-url="{{$data.RepoLink}}/issues/request_review?issue_ids={{$data.IssueID}}"{{end}}>
+<div class="issue-sidebar-combo" data-selection-mode="multiple" data-update-algo="diff"
+		{{if $pageMeta.Issue}}data-update-url="{{$pageMeta.RepoLink}}/issues/request_review?issue_ids={{$pageMeta.Issue.ID}}"{{end}}
+>
 	<input type="hidden" class="combo-value" name="reviewer_ids">{{/* match CreateIssueForm */}}
 	<div class="ui dropdown {{if or (not $hasCandidates) (not $data.CanChooseReviewer)}}disabled{{end}}">
 		<a class="text muted">
-			<strong>{{ctx.Locale.Tr "repo.issues.review.reviewers"}}</strong> {{if and $data.CanChooseReviewer}}{{svg "octicon-gear"}}{{end}}
+			<strong>{{ctx.Locale.Tr "repo.issues.review.reviewers"}}</strong> {{if $data.CanChooseReviewer}}{{svg "octicon-gear"}}{{end}}
 		</a>
 		<div class="menu flex-items-menu">
 			{{if $hasCandidates}}
@@ -29,7 +33,7 @@
 						<a class="item muted {{if .Requested}}checked{{end}}" href="#" data-value="{{.ItemID}}" data-can-change="{{.CanChange}}"
 							{{if not .CanChange}} data-tooltip-content="{{ctx.Locale.Tr "repo.issues.remove_request_review_block"}}"{{end}}>
 							<span class="item-check-mark">{{svg "octicon-check"}}</span>
-							{{svg "octicon-people" 20}} {{$data.RepoOwnerName}}/{{.Team.Name}}
+							{{svg "octicon-people" 20}} {{$repoOwnerName}}/{{.Team.Name}}
 						</a>
 					{{end}}
 				{{end}}
@@ -47,7 +51,7 @@
 					{{if .User}}
 						<a class="muted flex-text-inline" href="{{.User.HomeLink}}">{{ctx.AvatarUtils.Avatar .User 20}} {{.User.GetDisplayName}}</a>
 					{{else if .Team}}
-						{{svg "octicon-people" 20}} {{$data.RepoOwnerName}}/{{.Team.Name}}
+						{{svg "octicon-people" 20}} {{$repoOwnerName}}/{{.Team.Name}}
 					{{end}}
 				</div>
 				<div class="flex-text-inline">
@@ -64,13 +68,13 @@
 						{{if .Requested}}
 							<a href="#" class="ui muted icon link-action"
 								data-tooltip-content="{{ctx.Locale.Tr "repo.issues.remove_request_review"}}"
-								data-url="{{$data.RepoLink}}/issues/request_review?action=detach&issue_ids={{$data.IssueID}}&id={{.ItemID}}">
+								data-url="{{$pageMeta.RepoLink}}/issues/request_review?action=detach&issue_ids={{$pageMeta.Issue.ID}}&id={{.ItemID}}">
 								{{svg "octicon-trash"}}
 							</a>
 						{{else}}
 							<a href="#" class="ui muted icon link-action"
 								data-tooltip-content="{{ctx.Locale.Tr "repo.issues.re_request_review"}}"
-								data-url="{{$data.RepoLink}}/issues/request_review?action=attach&issue_ids={{$data.IssueID}}&id={{.ItemID}}">
+								data-url="{{$pageMeta.RepoLink}}/issues/request_review?action=attach&issue_ids={{$pageMeta.Issue.ID}}&id={{.ItemID}}">
 								{{svg "octicon-sync"}}
 							</a>
 						{{end}}
@@ -84,8 +88,8 @@
 		{{range $data.OriginalReviews}}
 			<div class="item">
 				<div class="flex-text-inline tw-flex-1">
-					{{$originalURLHostname := $data.Repository.GetOriginalURLHostname}}
-					{{$originalURL := $data.Repository.OriginalURL}}
+					{{$originalURLHostname := $pageMeta.Repository.GetOriginalURLHostname}}
+					{{$originalURL := $pageMeta.Repository.OriginalURL}}
 					<a class="muted flex-text-inline" href="{{$originalURL}}" data-tooltip-content="{{ctx.Locale.Tr "repo.migrated_from_fake" $originalURLHostname}}">
 						{{svg (MigrationIcon $originalURLHostname) 20}} {{.OriginalAuthor}}
 					</a>
@@ -108,7 +112,7 @@
 			<div class="ui warning message">
 				{{ctx.Locale.Tr "repo.issues.dismiss_review_warning"}}
 			</div>
-			<form class="ui form" action="{{$data.RepoLink}}/issues/dismiss_review" method="post">
+			<form class="ui form" action="{{$pageMeta.RepoLink}}/issues/dismiss_review" method="post">
 				{{ctx.RootData.CsrfTokenHtml}}
 				<input type="hidden" class="reviewer-id" name="review_id">
 				<div class="field">

templates/repo/issue/view_content/sidebar.tmpl

@@ -2,16 +2,19 @@
 	{{template "repo/issue/branch_selector_field" $}}
 
 	{{if .Issue.IsPull}}
-		{{template "repo/issue/sidebar/reviewer_list" $.IssueSidebarReviewersData}}
+		{{template "repo/issue/sidebar/reviewer_list" $.IssuePageMetaData}}
 		{{template "repo/issue/sidebar/wip_switch" $}}
 		<div class="divider"></div>
 	{{end}}
 
-	{{template "repo/issue/sidebar/label_list" $.IssueSidebarLabelsData}}
+	{{template "repo/issue/sidebar/label_list" $.IssuePageMetaData}}
+
+	{{template "repo/issue/sidebar/milestone_list" $.IssuePageMetaData}}
+	{{if .IsProjectsEnabled}}
+		{{template "repo/issue/sidebar/project_list" $.IssuePageMetaData}}
+	{{end}}
+	{{template "repo/issue/sidebar/assignee_list" $.IssuePageMetaData}}
 
-	{{template "repo/issue/sidebar/milestone_list" $}}
-	{{template "repo/issue/sidebar/project_list" $}}
-	{{template "repo/issue/sidebar/assignee_list" $}}
 	{{template "repo/issue/sidebar/participant_list" $}}
 	{{template "repo/issue/sidebar/watch_notification" $}}
 	{{template "repo/issue/sidebar/stopwatch_timetracker" $}}

web_src/css/repo.css

@@ -2453,12 +2453,6 @@ tbody.commit-list {
   margin-top: 1em;
 }
 
-.sidebar-item-link {
-  display: inline-flex;
-  align-items: center;
-  overflow-wrap: anywhere;
-}
-
 .diff-file-header {
   padding: 5px 8px !important;
   box-shadow: 0 -1px 0 1px var(--color-body); /* prevent borders being visible behind top corners when sticky and scrolled */

web_src/js/features/repo-issue-sidebar-combolist.ts

@@ -3,7 +3,7 @@ import {POST} from '../modules/fetch.ts';
 import {queryElemChildren, queryElems, toggleElem} from '../utils/dom.ts';
 
 // if there are draft comments, confirm before reloading, to avoid losing comments
-export function issueSidebarReloadConfirmDraftComment() {
+function issueSidebarReloadConfirmDraftComment() {
   const commentTextareas = [
     document.querySelector<HTMLTextAreaElement>('.edit-content-zone:not(.tw-hidden) textarea'),
     document.querySelector<HTMLTextAreaElement>('#comment-form textarea'),
@@ -22,84 +22,138 @@ export function issueSidebarReloadConfirmDraftComment() {
   window.location.reload();
 }
 
-function collectCheckedValues(elDropdown: HTMLElement) {
-  return Array.from(elDropdown.querySelectorAll('.menu > .item.checked'), (el) => el.getAttribute('data-value'));
-}
+class IssueSidebarComboList {
+  updateUrl: string;
+  updateAlgo: string;
+  selectionMode: string;
+  elDropdown: HTMLElement;
+  elList: HTMLElement;
+  elComboValue: HTMLInputElement;
+  initialValues: string[];
 
-export function initIssueSidebarComboList(container: HTMLElement) {
-  const updateUrl = container.getAttribute('data-update-url');
-  const elDropdown = container.querySelector<HTMLElement>(':scope > .ui.dropdown');
-  const elList = container.querySelector<HTMLElement>(':scope > .ui.list');
-  const elComboValue = container.querySelector<HTMLInputElement>(':scope > .combo-value');
-  let initialValues = collectCheckedValues(elDropdown);
+  constructor(private container: HTMLElement) {
+    this.updateUrl = this.container.getAttribute('data-update-url');
+    this.updateAlgo = container.getAttribute('data-update-algo');
+    this.selectionMode = container.getAttribute('data-selection-mode');
+    if (!['single', 'multiple'].includes(this.selectionMode)) throw new Error(`Invalid data-update-on: ${this.selectionMode}`);
+    if (!['diff', 'all'].includes(this.updateAlgo)) throw new Error(`Invalid data-update-algo: ${this.updateAlgo}`);
+    this.elDropdown = container.querySelector<HTMLElement>(':scope > .ui.dropdown');
+    this.elList = container.querySelector<HTMLElement>(':scope > .ui.list');
+    this.elComboValue = container.querySelector<HTMLInputElement>(':scope > .combo-value');
+  }
+
+  collectCheckedValues() {
+    return Array.from(this.elDropdown.querySelectorAll('.menu > .item.checked'), (el) => el.getAttribute('data-value'));
+  }
+
+  updateUiList(changedValues) {
+    const elEmptyTip = this.elList.querySelector('.item.empty-list');
+    queryElemChildren(this.elList, '.item:not(.empty-list)', (el) => el.remove());
+    for (const value of changedValues) {
+      const el = this.elDropdown.querySelector<HTMLElement>(`.menu > .item[data-value="${CSS.escape(value)}"]`);
+      if (!el) continue;
+      const listItem = el.cloneNode(true) as HTMLElement;
+      queryElems(listItem, '.item-check-mark, .item-secondary-info', (el) => el.remove());
+      this.elList.append(listItem);
+    }
+    const hasItems = Boolean(this.elList.querySelector('.item:not(.empty-list)'));
+    toggleElem(elEmptyTip, !hasItems);
+  }
+
+  async updateToBackend(changedValues) {
+    if (this.updateAlgo === 'diff') {
+      for (const value of this.initialValues) {
+        if (!changedValues.includes(value)) {
+          await POST(this.updateUrl, {data: new URLSearchParams({action: 'detach', id: value})});
+        }
+      }
+      for (const value of changedValues) {
+        if (!this.initialValues.includes(value)) {
+          await POST(this.updateUrl, {data: new URLSearchParams({action: 'attach', id: value})});
+        }
+      }
+    } else {
+      await POST(this.updateUrl, {data: new URLSearchParams({id: changedValues.join(',')})});
+    }
+    issueSidebarReloadConfirmDraftComment();
+  }
+
+  async doUpdate() {
+    const changedValues = this.collectCheckedValues();
+    if (this.initialValues.join(',') === changedValues.join(',')) return;
+    this.updateUiList(changedValues);
+    if (this.updateUrl) await this.updateToBackend(changedValues);
+    this.initialValues = changedValues;
+  }
+
+  async onChange() {
+    if (this.selectionMode === 'single') {
+      await this.doUpdate();
+      fomanticQuery(this.elDropdown).dropdown('hide');
+    }
+  }
 
-  elDropdown.addEventListener('click', (e) => {
+  async onItemClick(e) {
     const elItem = (e.target as HTMLElement).closest('.item');
     if (!elItem) return;
     e.preventDefault();
     if (elItem.hasAttribute('data-can-change') && elItem.getAttribute('data-can-change') !== 'true') return;
 
     if (elItem.matches('.clear-selection')) {
-      queryElems(elDropdown, '.menu > .item', (el) => el.classList.remove('checked'));
-      elComboValue.value = '';
+      queryElems(this.elDropdown, '.menu > .item', (el) => el.classList.remove('checked'));
+      this.elComboValue.value = '';
+      this.onChange();
       return;
     }
 
     const scope = elItem.getAttribute('data-scope');
     if (scope) {
       // scoped items could only be checked one at a time
-      const elSelected = elDropdown.querySelector<HTMLElement>(`.menu > .item.checked[data-scope="${CSS.escape(scope)}"]`);
+      const elSelected = this.elDropdown.querySelector<HTMLElement>(`.menu > .item.checked[data-scope="${CSS.escape(scope)}"]`);
       if (elSelected === elItem) {
         elItem.classList.toggle('checked');
       } else {
-        queryElems(elDropdown, `.menu > .item[data-scope="${CSS.escape(scope)}"]`, (el) => el.classList.remove('checked'));
+        queryElems(this.elDropdown, `.menu > .item[data-scope="${CSS.escape(scope)}"]`, (el) => el.classList.remove('checked'));
         elItem.classList.toggle('checked', true);
       }
     } else {
-      elItem.classList.toggle('checked');
-    }
-    elComboValue.value = collectCheckedValues(elDropdown).join(',');
-  });
-
-  const updateToBackend = async (changedValues) => {
-    let changed = false;
-    for (const value of initialValues) {
-      if (!changedValues.includes(value)) {
-        await POST(updateUrl, {data: new URLSearchParams({action: 'detach', id: value})});
-        changed = true;
+      if (this.selectionMode === 'multiple') {
+        elItem.classList.toggle('checked');
+      } else {
+        queryElems(this.elDropdown, `.menu > .item.checked`, (el) => el.classList.remove('checked'));
+        elItem.classList.toggle('checked', true);
       }
     }
-    for (const value of changedValues) {
-      if (!initialValues.includes(value)) {
-        await POST(updateUrl, {data: new URLSearchParams({action: 'attach', id: value})});
-        changed = true;
+    this.elComboValue.value = this.collectCheckedValues().join(',');
+    this.onChange();
+  }
+
+  async onHide() {
+    if (this.selectionMode === 'multiple') this.doUpdate();
+  }
+
+  init() {
+    // init the checked items from initial value
+    if (this.elComboValue.value && this.elComboValue.value !== '0' && !queryElems(this.elDropdown, `.menu > .item.checked`).length) {
+      const values = this.elComboValue.value.split(',');
+      for (const value of values) {
+        const elItem = this.elDropdown.querySelector<HTMLElement>(`.menu > .item[data-value="${CSS.escape(value)}"]`);
+        elItem?.classList.add('checked');
       }
+      this.updateUiList(values);
     }
-    if (changed) issueSidebarReloadConfirmDraftComment();
-  };
+    this.initialValues = this.collectCheckedValues();
 
-  const syncUiList = (changedValues) => {
-    const elEmptyTip = elList.querySelector('.item.empty-list');
-    queryElemChildren(elList, '.item:not(.empty-list)', (el) => el.remove());
-    for (const value of changedValues) {
-      const el = elDropdown.querySelector<HTMLElement>(`.menu > .item[data-value="${CSS.escape(value)}"]`);
-      const listItem = el.cloneNode(true) as HTMLElement;
-      queryElems(listItem, '.item-check-mark, .item-secondary-info', (el) => el.remove());
-      elList.append(listItem);
-    }
-    const hasItems = Boolean(elList.querySelector('.item:not(.empty-list)'));
-    toggleElem(elEmptyTip, !hasItems);
-  };
-
-  fomanticQuery(elDropdown).dropdown('setting', {
-    action: 'nothing', // do not hide the menu if user presses Enter
-    fullTextSearch: 'exact',
-    async onHide() {
-      // TODO: support "Esc" to cancel the selection. Use partial page loading to avoid losing inputs.
-      const changedValues = collectCheckedValues(elDropdown);
-      syncUiList(changedValues);
-      if (updateUrl) await updateToBackend(changedValues);
-      initialValues = changedValues;
-    },
-  });
+    this.elDropdown.addEventListener('click', (e) => this.onItemClick(e));
+
+    fomanticQuery(this.elDropdown).dropdown('setting', {
+      action: 'nothing', // do not hide the menu if user presses Enter
+      fullTextSearch: 'exact',
+      onHide: () => this.onHide(),
+    });
+  }
+}
+
+export function initIssueSidebarComboList(container: HTMLElement) {
+  new IssueSidebarComboList(container).init();
 }

web_src/js/features/repo-issue-sidebar.md

@@ -1,7 +1,7 @@
 A sidebar combo (dropdown+list) is like this:
 
 ```html
-<div class="issue-sidebar-combo" data-update-url="...">
+<div class="issue-sidebar-combo" data-selection-mode="..." data-update-url="...">
   <input class="combo-value" name="..." type="hidden" value="...">
   <div class="ui dropdown">
     <div class="menu">
@@ -25,3 +25,7 @@ If there is `data-update-url`, it also calls backend to attach/detach the change
 Also, the changed items will be syncronized to the `ui list` items.
 
 The items with the same data-scope only allow one selected at a time.
+
+The dropdown selection could work in 2 modes:
+* single: only one item could be selected, it updates immediately when the item is selected.
+* multiple: multiple items could be selected, it defers the update until the dropdown is hidden.

web_src/js/features/repo-issue-sidebar.ts

@@ -1,10 +1,7 @@
 import $ from 'jquery';
 import {POST} from '../modules/fetch.ts';
-import {updateIssuesMeta} from './repo-common.ts';
-import {svg} from '../svg.ts';
-import {htmlEscape} from 'escape-goat';
 import {queryElems, toggleElem} from '../utils/dom.ts';
-import {initIssueSidebarComboList, issueSidebarReloadConfirmDraftComment} from './repo-issue-sidebar-combolist.ts';
+import {initIssueSidebarComboList} from './repo-issue-sidebar-combolist.ts';
 
 function initBranchSelector() {
   const elSelectBranch = document.querySelector('.ui.dropdown.select-branch');
@@ -34,212 +31,6 @@ function initBranchSelector() {
   });
 }
 
-// List submits
-function initListSubmits(selector, outerSelector) {
-  const $list = $(`.ui.${outerSelector}.list`);
-  const $noSelect = $list.find('.no-select');
-  const $listMenu = $(`.${selector} .menu`);
-  let hasUpdateAction = $listMenu.data('action') === 'update';
-  const items = {};
-
-  $(`.${selector}`).dropdown({
-    'action': 'nothing', // do not hide the menu if user presses Enter
-    fullTextSearch: 'exact',
-    async onHide() {
-      hasUpdateAction = $listMenu.data('action') === 'update'; // Update the var
-      if (hasUpdateAction) {
-        // TODO: Add batch functionality and make this 1 network request.
-        const itemEntries = Object.entries(items);
-        for (const [elementId, item] of itemEntries) {
-          await updateIssuesMeta(
-            item['update-url'],
-            item['action'],
-            item['issue-id'],
-            elementId,
-          );
-        }
-        if (itemEntries.length) {
-          issueSidebarReloadConfirmDraftComment();
-        }
-      }
-    },
-  });
-
-  $listMenu.find('.item:not(.no-select)').on('click', function (e) {
-    e.preventDefault();
-    if (this.classList.contains('ban-change')) {
-      return false;
-    }
-
-    hasUpdateAction = $listMenu.data('action') === 'update'; // Update the var
-
-    const clickedItem = this; // eslint-disable-line unicorn/no-this-assignment
-    const scope = this.getAttribute('data-scope');
-
-    $(this).parent().find('.item').each(function () {
-      if (scope) {
-        // Enable only clicked item for scoped labels
-        if (this.getAttribute('data-scope') !== scope) {
-          return;
-        }
-        if (this !== clickedItem && !this.classList.contains('checked')) {
-          return;
-        }
-      } else if (this !== clickedItem) {
-        // Toggle for other labels
-        return;
-      }
-
-      if (this.classList.contains('checked')) {
-        $(this).removeClass('checked');
-        $(this).find('.octicon-check').addClass('tw-invisible');
-        if (hasUpdateAction) {
-          if (!($(this).data('id') in items)) {
-            items[$(this).data('id')] = {
-              'update-url': $listMenu.data('update-url'),
-              action: 'detach',
-              'issue-id': $listMenu.data('issue-id'),
-            };
-          } else {
-            delete items[$(this).data('id')];
-          }
-        }
-      } else {
-        $(this).addClass('checked');
-        $(this).find('.octicon-check').removeClass('tw-invisible');
-        if (hasUpdateAction) {
-          if (!($(this).data('id') in items)) {
-            items[$(this).data('id')] = {
-              'update-url': $listMenu.data('update-url'),
-              action: 'attach',
-              'issue-id': $listMenu.data('issue-id'),
-            };
-          } else {
-            delete items[$(this).data('id')];
-          }
-        }
-      }
-    });
-
-    // TODO: Which thing should be done for choosing review requests
-    // to make chosen items be shown on time here?
-    if (selector === 'select-assignees-modify') {
-      return false;
-    }
-
-    const listIds = [];
-    $(this).parent().find('.item').each(function () {
-      if (this.classList.contains('checked')) {
-        listIds.push($(this).data('id'));
-        $($(this).data('id-selector')).removeClass('tw-hidden');
-      } else {
-        $($(this).data('id-selector')).addClass('tw-hidden');
-      }
-    });
-    if (!listIds.length) {
-      $noSelect.removeClass('tw-hidden');
-    } else {
-      $noSelect.addClass('tw-hidden');
-    }
-    $($(this).parent().data('id')).val(listIds.join(','));
-    return false;
-  });
-  $listMenu.find('.no-select.item').on('click', function (e) {
-    e.preventDefault();
-    if (hasUpdateAction) {
-      (async () => {
-        await updateIssuesMeta(
-          $listMenu.data('update-url'),
-          'clear',
-          $listMenu.data('issue-id'),
-          '',
-        );
-        issueSidebarReloadConfirmDraftComment();
-      })();
-    }
-
-    $(this).parent().find('.item').each(function () {
-      $(this).removeClass('checked');
-      $(this).find('.octicon-check').addClass('tw-invisible');
-    });
-
-    if (selector === 'select-assignees-modify') {
-      return false;
-    }
-
-    $list.find('.item').each(function () {
-      $(this).addClass('tw-hidden');
-    });
-    $noSelect.removeClass('tw-hidden');
-    $($(this).parent().data('id')).val('');
-  });
-}
-
-function selectItem(select_id, input_id) {
-  const $menu = $(`${select_id} .menu`);
-  const $list = $(`.ui${select_id}.list`);
-  const hasUpdateAction = $menu.data('action') === 'update';
-
-  $menu.find('.item:not(.no-select)').on('click', function () {
-    $(this).parent().find('.item').each(function () {
-      $(this).removeClass('selected active');
-    });
-
-    $(this).addClass('selected active');
-    if (hasUpdateAction) {
-      (async () => {
-        await updateIssuesMeta(
-          $menu.data('update-url'),
-          '',
-          $menu.data('issue-id'),
-          $(this).data('id'),
-        );
-        issueSidebarReloadConfirmDraftComment();
-      })();
-    }
-
-    let icon = '';
-    if (input_id === '#milestone_id') {
-      icon = svg('octicon-milestone', 18, 'tw-mr-2');
-    } else if (input_id === '#project_id') {
-      icon = svg('octicon-project', 18, 'tw-mr-2');
-    } else if (input_id === '#assignee_id') {
-      icon = `<img class="ui avatar image tw-mr-2" alt="avatar" src=${$(this).data('avatar')}>`;
-    }
-
-    $list.find('.selected').html(`
-        <a class="item muted sidebar-item-link" href="${htmlEscape(this.getAttribute('data-href'))}">
-          ${icon}
-          ${htmlEscape(this.textContent)}
-        </a>
-      `);
-
-    $(`.ui${select_id}.list .no-select`).addClass('tw-hidden');
-    $(input_id).val($(this).data('id'));
-  });
-  $menu.find('.no-select.item').on('click', function () {
-    $(this).parent().find('.item:not(.no-select)').each(function () {
-      $(this).removeClass('selected active');
-    });
-
-    if (hasUpdateAction) {
-      (async () => {
-        await updateIssuesMeta(
-          $menu.data('update-url'),
-          '',
-          $menu.data('issue-id'),
-          $(this).data('id'),
-        );
-        issueSidebarReloadConfirmDraftComment();
-      })();
-    }
-
-    $list.find('.selected').html('');
-    $list.find('.no-select').removeClass('tw-hidden');
-    $(input_id).val('');
-  });
-}
-
 function initRepoIssueDue() {
   const form = document.querySelector<HTMLFormElement>('.issue-due-form');
   if (!form) return;
@@ -257,14 +48,6 @@ export function initRepoIssueSidebar() {
   initBranchSelector();
   initRepoIssueDue();
 
-  // TODO: refactor the legacy initListSubmits&selectItem to initIssueSidebarComboList
-  initListSubmits('select-assignees', 'assignees');
-  initListSubmits('select-assignees-modify', 'assignees');
-  selectItem('.select-assignee', '#assignee_id');
-
-  selectItem('.select-project', '#project_id');
-  selectItem('.select-milestone', '#milestone_id');
-
   // init the combo list: a dropdown for selecting items, and a list for showing selected items and related actions
   queryElems<HTMLElement>(document, '.issue-sidebar-combo', (el) => initIssueSidebarComboList(el));
 }